Looking for a voicemail product

I’ll be traveling abroad for 2-3 weeks next month, during which I will not have access to my phone (don’t plan to take international roaming). In this context, what I need is some kind of a voicemail product – where any call made to my airtel number (which will be “switched off”) will get redirected to voicemail, which informs the caller that I’m traveling and they should leave a message. And I should be able to log on periodically to some website where I can listen to my collected voicemail, and possibly call back some of them.

Does such a product exist? If not, does there exist a market for this, or does everyone who wants to use a product like this can afford international roaming?

And while we are at it, are there any good voicemail apps that I can use on my Android phone (when my phone is in the sim and connected to the network)?

Thanks much!